The present invention relates to a method for producing a palladium-phosphine complex compound, which is useful as a catalyst of organic synthesis.
Hitherto, various transition metal complexes have been used as catalysts of organic synthesis. In particular, noble metal complexes are stable and easy to handle. Thus, they are widely used as catalysts for organic synthesis, although they are high in price. Of optically active ligands of transition metal complexes used in asymmetric catalytic reactions, a ligand of 2,2xe2x80x2-bis(diphenylphosphino)-1,1xe2x80x2-binaphtyl (hereinafter referred to as xe2x80x9cBINAPxe2x80x9d) is one of the most superior ligands in asymmetry differentiation capability. It has been reported in J. Am. Chem. Soc., 1991, Vol. 113, pp. 1417 and J. Org. Chem., 1989, Vol. 54, pp. 4738 that a palladium complex having a ligand of BINAP is very much superior in catalytic activity, particularly in enantio-selectivity, for Heck reaction to an olefin, which is an asymmetric carbon-carbon bond formation reaction. In such reaction, there is assumed an involvement of an intermediate of [PhPd(I)(BINAP)], which is formed by an oxidative addition of benzene iodide to Pd(0)-BINAP formed in the reaction system.
There are known palladium complex compounds having ligands of trifluoromethylphenyl and tris(trifluoromethyl)phenyl, which are represented by the general formulas: 
where Y is fluorine, chlorine, bromine, or iodine.
J. Organomet. Chem., 1971, 28, 287 discloses a method for producing a palladium complex compound represented by the general formula Ar1Pd(PPh3)2X1 where Ar1 represents an aryl and X1 is a halogen. In this method, a stable palladium complex Pd0(PPh3)4 is reacted with an aryl halide. Organometallics, 1996, 15(17), 3708 discloses a similar method in which a palladium complex Pd2(dba)3 is used.
J. Chem. Commun., 1994, 121 discloses a reaction of dibromobis(triphenylphosphine)palladium(II) with toluene in the presence of potassium carbonate at 130 for 1 hr to obtain a small amount of bromo[methylphenyl]bis(triphenylphosphine)palladium(II).
J. Am. Chem. Soc., Vol. 117, No. 15, 4305 (1995) discloses a method for producing a palladium complex compound having a benzoato ligand, represented by the formula (Ph3P)2PdPh(PhCOO). In this method, (Ph3P)2Pd2Ph2(xcexc-OH)2 is dispersed in benzene. Then, benzoic acid is added to the mixture to have a solution having a pale yellow color. Then, the solvent is distilled away. After that, n-hexane is added, thereby obtaining (Ph3P)2Pd2Ph2(xcexc-PhCOO)2 in the form of crystal. The obtained crystals are dispersed in benzene. Then, triphenylphosphine is added, thereby preparing a transparent solution. Then, the solvent is distilled away. After that, n-hexane is added, thereby obtaining the aimed palladium complex compound in the form of crystal.
J. Organomet. Chem. 553 (1998) 83-90 discloses a method for producing trans-[Pd(OOCxe2x80x94(C6H4)-2-SMexe2x80x94xcexa1xe2x80x94O)Ph(PPh3)2]. In this method, a thallium salt 2-RSxe2x80x94C6H4xe2x80x94COOTl is prepared by reacting 2-RSxe2x80x94C6H4xe2x80x94COOH with thallium carbonate in ethanol. Then, the thallium salt is reacted with trans-[PdCl(Ph) (PPh3)2] in tetrahydrofuran, thereby obtaining the product with a precipitate of thallium chloride.
It is an object of the present invention to provide a method for easily producing a palladium complex compound that is useful as catalyst.
It is another object of the present invention to provide a palladium complex compound that is superior in physical and/or chemical properties.
According to a first aspect of the present invention, there is provided a first method for producing a first palladium-complex compound represented by the general formula (4). With this, it is possible to easily obtain the product by the following reaction steps (a) and (b). The first method comprises:
(a) reacting an aromatic compound represented by the general formula (1), with a palladium compound and a phosphine derivative, in the presence of a first basic substance, thereby obtaining a second palladium-complex compound represented by the general formula (2); and
(b) reacting said second palladium-complex compound with a benzoic acid represented by the general formula (3), in the presence of a second basic substance, thereby producing said first palladium-complex compound,
Ar1Xxe2x80x83xe2x80x83(1)
xe2x80x83where Ar1 is an aryl group; and X is a halogen that is fluorine, chlorine, bromine or iodine, trifluoromethanesulfonate group, an alkylsulfonate group having a carbon atom number of 1-4, or a substituted or unsubstituted arylsulfonate group,
Ar1xe2x80x94PdL2Xxe2x80x83xe2x80x83(2)
xe2x80x83where each L is independently a phosphine ligand, and Ar1 and X are defined as above,
Ar2xe2x80x94COOHxe2x80x83xe2x80x83(3)
xe2x80x83where Ar2 is an aryl group, 
xe2x80x83where Ar1, Ar2, and L are defined as above.
According to a second aspect of the invention, there is provided a second method for producing the second palladium-complex compound represented by the general formula (2). With this, it becomes possible to easily obtain the product, using stable chemical substances that are easily obtainable. The second method comprises the reaction step (a) of the first method, thereby obtaining the second palladium-complex compound.
According to a third aspect of the invention, there is provided a third method for producing the first palladium-complex compound represented by the general formula (4). The third method comprises reacting a second palladium-complex compound represented by the general formula (2), with a benzoic acid represented by the general formula (3), in the presence of a basic substance, thereby producing the first palladium-complex compound.
According to a fourth aspect of the invention, there is provided a fourth method for producing the first palladium-complex compound represented by the general formula (4). As compared with the first method, the fourth method comprises a single reaction step of reacting an aromatic compound represented by the general formula (1), with a palladium compound, a phosphine derivative and a benzoic acid derivative represented by the general formula (3), in the presence of a basic substance, thereby obtaining the first palladium-complex compound.
According to a fifth aspect of the invention, there is provided a novel palladium complex compound. This compound, which can be produced by the above-mentioned first, third or fourth method, is represented by the general formula (5), 
where Ar3 and Ar4 are respectively aryl groups represented by the general formulas (6) and (7), and each L is independently a phosphine ligand, 
where R2 is trifluoromethyl group, trifluoromethyoxy group, a halogen that is fluorine, chlorine, bromine or iodine, nitro group, acetyl group, cyano group, an alkyl group having a carbon atom number of 1-4, an alkoxyl group having a carbon atom number of 1-4, or an alkoxycarbonyl group having a carbon atom number of 2-5; and m is an integer of 0-4, 
where R1 is trifluoromethyl group, and n is an integer of 1-3.
According to a sixth aspect of the invention, there is provided a novel palladium complex compound. This compound, which can be produced by the above-mentioned second method, is represented by the general formula Ar5xe2x80x94PdL2X where Ar5 is bis(trifluoromethyl)phenyl group, X is halogen that is fluorine, chlorine, bromine or iodine, and each L is independently a phosphine ligand.
The above-mentioned first to fourth methods according to the invention will be described in detail, as follows.
In the aromatic compound Ar1X used in the first, second and fourth methods and the second palladium-complex compound Ar1xe2x80x94PdL2X used in the third method, X is defined as above and preferably bromine or iodine in practical use.
In the aromatic compound Ar1X used in the first, second and fourth methods and the second palladium-complex compound Ar1xe2x80x94PdL2X used in the third method, Ar1 is defined as being an aryl group, as mentioned above. This aryl group Ar1 can be selected from carbon cyclic groups, such as phenyl and naphthyl, and heterocyclic groups, such as pyridyl and quinolyl. These groups may have substituents. The aryl group Ar1 is preferably one represented by the general formula (6). 
where R2 is a halogen that is fluorine, chlorine, bromine or iodine, or a monovalent organic group, and m is an integer of 0-4. The substituent R2 is not particularly limited so long as it is inert in the reaction of the invention.
In the benzoic acid Ar2xe2x80x94COOH used in the first, third and fourth methods, Ar2 is also defined as being an aryl group, as mentioned above. This aryl group Ar2 can also be selected from the above-mentioned exemplary groups of the aryl group Ar1. The exemplary groups of the aryl group Ar2 may also have substituents. The aryl group Ar2 is preferably one represented by the general formula (7), 
where R1 is defined as R2 of the general formula (6) and n is an integer of 0-3. The substituent R1 is not particularly limited so long as it is inert in the reaction of the invention.
Examples of the substituents R1 and R2 in the general formulas (6) and (7) are trifluoromethyl group, trifluoromethyoxy group, halogens that are fluorine, chlorine, bromine and iodine, nitro group, acetyl group, cyano group, alkyl groups each having a carbon atom number of 1-4, alkoxyl groups each having a carbon atom number of 1-4, and alkoxycarbonyl groups each having a carbon atom number of 2-5. Examples of the alkyl group are methyl group, ethyl group, n-propyl group, and i-propyl group. Examples of the alkoxyl group are methoxy group, ethoxy group, n-propoxy group, and i-propoxy group. Examples of the alkoxycarbonyl group are methoxycarbonyl group, ethoxycarbonyl group, n-propoxycarbonyl group, and i-propoxycarbonyl group. The aryls group Ar1 is preferably one in which at least one of R2 is trifluoromethyl group. The aryl group Ar2 is also preferably one in which at least one of R1 is trifluoromethyl group.
Examples of the aryl groups Ar1 and Ar2 used in the first to fourth methods are (1) aryl groups each having one trifluoromethyl, such as 2-trifluoromethylphenyl, 3-trifluoromethylphenyl, and 4-trifluoromethylphenyl, (2) aryl groups each having one trifluoromethoxy, such as 2-trifluoromethoxyphenyl, 3-trifluoromethoxyphenyl, and 4-trifluoromethoxyphenyl, (3) aryl groups each having one fluorine, such as 2-fluorophenyl, 3-fluorophenyl, and 4-fluorophenyl, (4) aryl groups each having one chlorine, such as 2-chlorophenyl, 3-chlorophenyl, and 4-chlorophenyl, (5) aryl groups each having one bromine, such as 2-bromorophenyl, 3-bromorophenyl, and 4-bromorophenyl, (6) aryl groups each having one iodine, such as 2-iodophenyl, 3-iodophenyl, and 4-iodophenyl, (7) aryl groups each having one nitro group, such as 2-nitrophenyl, 3-nitrophenyl, and 4-nitrophenyl, (8) aryl groups each having one acetyl, such as 2-acetylphenyl, 3-acetylphenyl, and 4-acetylphenyl, (9) aryl groups each having one cyano group, such as 2-cyanophenyl, 3-cyanophenyl, and 4-cyanophenyl, (11) aryl groups each having one alkyl, such as 2-methylphenyl, 3-methylphenyl, 4-methylphenyl, 2-ethylphenyl, 3-ethylphenyl, and 4-ethylphenyl, (12) aryl groups each having one alkoxy, such as 2-methoxyphenyl, 3-methoxyphenyl, 4-methoxyphenyl, 2-ethoxyphenyl, 3-ethoxyphenyl, and 4-ethoxyphenyl, and (13) aryl groups each having one alkoxycarbonyl, such as 2-methoxycarbonylphenyl, 3-methoxycarbonylphenyl, 4-methoxycarbonylphenyl, 2-ethoxycarbonylphenyl, 3-ethoxycarbonylphenyl, and 4-ethoxycarbonylphenyl. Each of the aryl groups Ar1 and Ar2 may have at least two substituents. These at least two substituents may be any arbitrary combination of various substituents. One of the at least two substituents of the aryl group Ar1 or Ar2 is preferably trifluoromethyl group. Nonlimitative examples of such aryl groups Ar1 and Ar2 are 2-chloro-3-(trifluoromethyl)phenyl, 2-fluoro-3-(trifluoromethyl)phenyl, 2-fluoro-4-(trifluoromethyl)phenyl, 3-fluoro-5-(trifluoromethyl)phenyl, 2-bromo-6-(trifluoromethyl)phenyl, 4-chloro-2-(trifluoromethyl)phenyl, 4-fluoro-2-(trifluoromethyl)phenyl, 2-chloro-6-(trifluoromethyl)phenyl, 4-fluoro-3-(trifluoromethyl)phenyl, 1-chloro-4-(trifluoromethyl)phenyl, 2-fluoro-6-(trifluoromethyl)phenyl, 2-fluoro 5-(trifluoromethyl)phenyl, 2-chloro-4-(trifluoromethyl)phenyl, 4-chloro-3-(trifluoromethyl)phenyl, 4-chloro-2-(trifluoromethyl)phenyl and the like; 2-methyl-3-(trifluoromethyl)phenyl, 3-methyl-5-(trifluoromethyl)phenyl, 2-methyl-4-(trifluoromethyl)phenyl, 4,5-dimethyl-2-(trifluoromethyl)phenyl, 2-methyl-5-(trifluoromethyl)phenyl, 5,6-dimethyl-2-(trifluoromethyl)phenyl, 4-methyl-3-(trifluoromethyl)phenyl, and the like; 2-methoxy-4-(trifluoromethyl)phenyl, 2-ethoxy-4-(trifluoromethyl)phenyl, 4-ethoxy-2-(trifluoromethyl)phenyl, 4-methoxy-2-(trifluoromethyl)phenyl, 2-methoxy-5-(trifluoromethyl)phenyl, and the like; 2-nitro-3-(trifluoromethyl)phenyl, 2-nitro-4-(trifluoromethyl)phenyl, 4-nitro-2-(trifluoromethyl)phenyl, 3-nitro-5-(trifluoromethyl)phenyl, 2-nitro-5-(trifluoromethyl)phenyl, 4-nitro-3-(trifluoromethyl)phenyl, and the like; 2-cyano-5-(trifluoromethyl)phenyl, 2-cyano-4-(trifluoromethyl)phenyl, 4-fluoro-3-cyano-5-(trifluoromethyl)phenyl, 4-cyano-3-(trifluoromethyl)phenyl, 2-chloro-5-cyano-3-(trifluoromethyl)phenyl, 4-cyano-2-(trifluoromethyl)phenyl, and the like; and 2-amino-6-(trifluoromethyl)phenyl, 2-amino-5-(trifluoromethyl)phenyl, 2-amino-4-(trifluoromethyl)phenyl, 2-amino-3-(trifluoromethyl)phenyl, 3-amino-6-(trifluoromethyl)phenyl, 3-amino-5-(trifluoromethyl)phenyl, 4-amino-2-(trifluoromethyl)phenyl, 4-amino-3-(trifluoromethyl)phenyl, and the like. Each aryl group Ar1 or Ar2 is preferably one having at least two trifluoromethyl groups. Examples of such aryl group are 2,3-bis(trifluoromethyl)phenyl, 2,4-bis(trifluoromethyl)phenyl, 2,5-bis(trifluoromethyl)phenyl, 2,6-bis(trifluoromethyl)phenyl, 3,4-bis(trifluoromethyl)phenyl, and 3,5-bis(trifluoromethyl)phenyl. Further nonlimitative examples of such aryl group are 2,3,4-tris(trifluoromethyl)phenyl, 2,4,5-tris(trifluoromethyl)phenyl, 2,3,5-tris(trifluoromethyl)phenyl, 1,3,5-tris(trifluoromethyl)phenyl, 3,4,5-tris(trifluoromethyl)phenyl, 2,3,4,6-tetrakis(trifluoromethyl)phenyl, 1-bromo-2,3,4-tris(trifluoromethyl)phenyl, 2-bromo-4,5,6-tris(trifluoromethyl)phenyl, and the like; and 3,5-dichloro-4,6-bis(trifluoromethyl)phenyl, 2-dichloro-3,5-bis(trifluoromethyl)phenyl, 2-methoxy-3,5-bis(trifluoromethyl)phenyl, 2-bromo-3,5-bis(trifluoromethyl)phenyl, 2-nitro-4,6-bis(trifluoromethyl)phenyl, 5,6-dichloro-1,3-bis(trifluoromethyl)phenyl, 4-chloro-3,5-bis(trifluoromethyl)phenyl, and the like.
The second palladium-complex compound (Ar1xe2x80x94PdL2X), which is used in the third method of the invention, is preferably one in which at least one of R2 is trifluoromethyl group and more preferably one in which at least two of R2 are trifluoromethyl groups, since the aimed product becomes extremely useful. The benzoic acid (Ar2xe2x80x94COOH), which is used in the first, third and fourth methods of the invention, is preferably one in which at least one of R1 is trifluoromethyl group and more preferably one in which at least two of R1 are trifluoromethyl groups, since the aimed product becomes extremely useful.
As stated above, the starting material of the third method is the second palladium-complex compound represented by the general formula (2), Ar1xe2x80x94PdL2X, where each L is independently a phosphine ligand. Furthermore, the phosphine derivative is used in the first, second and fourth lo methods. Such phosphine (phosphine derivative or phosphine ligand) used in the first to fourth methods is not particularly limited and may be one represented by the general formula P(R1)3, which can be a monodentate ligand in Ar1xe2x80x94PdL2X, where each R1 is independently a first group selected from the group consisting of lower alkyl groups, cycloalkyl groups, phenyl group, naphthyl group, anthryl group, pyridyl group and quinolyl group. The first group optionally has a first substituent R2 selected from the group consisting of nitro group, primary amino group, secondary amino group, tertiary amino group, halogen atoms, and a second substituent. The second substituent is selected from the group consisting of lower alkyl groups, cycloalkyl groups, phenyl group, naphthyl group, anthryl group, pyridyl group and quinolyl group. The second substituent optionally has a third substituent R3 selected from the group consisting of nitro group, primary amino group, secondary amino group, tertiary amino group, halogen atoms, and a substituent being selected from the group consisting of lower alkyl groups, lower alkoxy groups, cycloalkyl groups, phenyl group, naphthyl group, anthryl group, pyridyl group, and quinolyl group. The substituent optionally has a substituent. In the present application, xe2x80x9clower alkyl groupsxe2x80x9d, for example, of the above-mentioned phosphine, can be straight chain or branched alkyl groups each having a carbon atom number of 1-6. Examples of such lower alkyl groups are methyl group (hereinafter may be referred to as xe2x80x9cMexe2x80x9d), ethyl group, n-propyl group, i-propyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, and n-hexyl group. In the present application, xe2x80x9clower alkoxy groupsxe2x80x9d, for example, of the above-mentioned phosphine can be straight chain or branched alkoxy groups each having a carbon atom number of 1-6. Examples of such lower alkoxy groups are methoxy group (hereinafter may be referred to as xe2x80x9cMeOxe2x80x9d), ethoxy group, n-propoxy group, i-propoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentoxy group, and n-hexyloxy group.
In the above-mentioned phosphine represented by the general formula P(R1)3, at least one of R1 is preferably phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-acynyl group, or 3,5-xylyl group. Concrete examples of such phosphine are triphenylphosphine, tris(o-tolyl)phosphine, tris(m-tolyl)phosphine, tris(p-tolyl)phosphine, tris(4-acynyl)phosphine, tris(3,5-xylyl)phosphine, and tris(n-butyl)phosphine. Of these, triphenylphosphine is particularly preferable. The phosphine P(R1)3 can be a first one represented by the following formula: 
where n is an integer of 1-2, an arbitrary number of hydrogen atoms of the condensed ring may be replaced with the above-defined first substituent R2, and each R4 is independently phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-acynyl group, or 3,5-xylyl group. Such phosphine P(R1)3 can be a second one represented by the following formula: 
where an arbitrary number of hydrogen atoms of the naphthalene ring may be replaced with the above-defined first substituent R2, and each R4 is defined as above. Furthermore, the phosphine P(R1)3 can be a third one represented by the following formula: 
where an arbitrary number of hydrogen atoms of the naphthalene ring may be replaced with lower alkyl groups or lower alkoxy groups, and each R4 is defined as above. Furthermore, the phosphine P(R1)3 can be a fourth one represented by the following formula: 
where R5 is a lower alkyl group, and each R4 is defined as above. Furthermore, the phosphine P(R1)3 can be fifth one represented by the following formula: 
where each R4 is defined as above. A preferable example of the second palladium-complex compound containing the above fifth phosphine, which can be used as the starting material of the third method, is one represented by the following formula: 
where X is a halogen that is fluorine, chlorine, bromine or iodine, trifluoromethanesulfonate group, an alkylsulfonate group having a carbon atom number of 1-4, or a substituted or unsubstituted arylsulfonate group. La this second palladium-complex compound, X is preferably bromine, and two of the trifluoromethyl group are particularly preferably bonded to the 3- and 5-positions.
The phosphine (i.e., phosphine derivative or phosphine ligand) used in the first to fourth method may be one represented by the general formula (R1)2Pxe2x80x94Qxe2x80x94P(R1)2, which can be a bidentate ligand in Ar1xe2x80x94PdL2X, where each R1 is defined as in the phosphine P(R1)3, and Q is a bivalent group. In the phosphine (R1)2Pxe2x80x94Qxe2x80x94P(R1)2, at least one of R1 is preferably phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, 4-acynyl group, or 3,5-xylyl group. The bivalent group Q may comprise (1) an arbitrary number of a first bivalent group selected from alkylene group, phenylene group, naphthylene group, and anthrylene group, and (2) an arbitrary number of a bonding group selected from the group consisting of single bond, xe2x80x94Oxe2x80x94, xe2x80x94Sxe2x80x94, xe2x80x94C(xe2x95x90O)xe2x80x94, and xe2x80x94S(xe2x95x90O)xe2x80x94. The first bivalent group optionally has an arbitrary number of a substituent that can be selected from nitro group, primary amino group, secondary amino group, tertiary amino group, halogen atoms, lower alkyl groups, lower alkoxy groups, cycloalkyl groups, phenyl group, naphthyl group, anthryl group, pyridyl group, and quinolyl group. The bivalent group Q can be a preferable one selected from alkylene group, biphenylene group, binaphthylene group and bianthrylene group. This preferable one optionally has an arbitrary number of a group selected from nitro group, primary amino group, secondary amino group, tertiary amino group, halogen atoms, lower alkyl groups, lower alkoxy groups, cycloalkyl groups, phenyl group, naphthyl group, anthryl group, pyridyl group, and quinolyl group. The phosphine (R1)2Pxe2x80x94Qxe2x80x94P(R1)2 can be a first one represented by the following general formula: 
where an arbitrary number of hydrogen atoms of each aromatic ring may be replaced with the above-defined first substituent R2, R4 is defined as in the first one of the phosphine P(R1)3, each of m and n is independently an integer of 0-2. Furthermore, the phospine (R1)2Pxe2x80x94Qxe2x80x94P(R1)2 can be a second one represented by the following general formula: 
where an arbitrary number of hydrogen atoms of each aromatic ring may be replaced with the above-defined first substituent R2, and R4 is defined as in the first one of the phosphine P(R1)3. Furthermore, the phosphine (R1)2Pxe2x80x94Qxe2x80x94P(R1)2 can be a third one represented by the following general formula: 
where an arbitrary number of hydrogen atoms of each aromatic ring may be replaced with a lower alkyl group or a lower alkoxy group. A preferable example of the second palladium-complex compound containing the above third phosphine (R1)2Pxe2x80x94Qxe2x80x94P(R1)2, which can be used as the starting material of the third method, is one represented by the following formula: 
where X is a halogen that is fluorine, chlorine, bromine or iodine, trifluoromethanesulfonate group, an alkylsulfonate group having a carbon atom number of 1-4, or a substituted or unsubstituted arylsulfonate group. In this second palladium-complex compound, X is preferably bromine, and two of the trifluoromethyl group are particularly preferably bonded to the 3- and 5-positions.
The phosphine (i.e., the phosphine derivative or phosphine ligand) may be one represented by the general formula (R4)2Pxe2x80x94(CH2)qxe2x80x94P(R4)2 where R4 is defined as above, and q is an integer of 2-8. Furthermore, the phosphine may be one represented by the general formula Ph2Pxe2x80x94(CH2)qxe2x80x94PPh2 where q is an integer of 2-8.
The palladium compound, which is used in the first, second and fourth methods, is preferably a palladium salt, such as palladium acetate, palladium chloride, palladium bromide, palladium iodide, or palladium nitrate. Furthermore, the palladium compound can be a palladium-complex(lI), such as [Pd(NH3)4]Y2, Pd(NH3)2Y2, Pd(NH3)4, or PdY4, where Y is halogen that is chlorine, bromine or iodine.
The basic substance, which is used in the first to fourth methods, including each of the first and second basic substances used in the first method, is not limited to a particular type. Nonlimitative examples of the basic substance are (1) ammonia and the like, such as ammonia and hydroxyamine, (2) amines, such as primary amine, secondary amine, tertiary amine, alicyclic amine (e.g., cyclopropylamine), and aromatic amine, and (3) inorganic bases, such as acetate (e.g., sodium acetate and potassium acetate), sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. Examples of the primary amine are propylamine, isopropylamine, butylamine, amylamine, and hexylamine. Examples of the secondary amine are diethylamine, dipropylamine, diisopropylamine, and dibutylamine. Examples of the third amine are triethylamine, tripropylamine, and tributylamine. Examples of the aromatic amine are triarylamine, N,N-dimethylaniline, N,N-diethylaniline, pyridine, and N-methylmorpholine.
It is optional to use a solvent in the first to fourth methods of the invention. Examples of such solvent are (1) aliphatic hydrocarbons, such as pentane, hexane, heptane, and octane, (2) aromatic hydrocarbons, such as benzene, toluene, and xylene, (3) ethers, such as diethyl ether, dioxane, tetrahydrofuran (THF), and ethylene glycol dimethyl ether, (4) ketones, such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, (5) nitrites such as acetonitrile, (6) tertiary amines such as pyridine, (7) acid amides, such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc), (8) sulfur-containing compounds, such as dimethylsulfoxide (DMSO) and sulforane, and (9) water. In case that a water-soluble basic substance is used in the reaction, it is preferable to use water, optionally together with one other solvent. Furthermore, the aromatic compound Ar1X itself, which is used in the first, second and fourth methods, can be used as a reaction solvent.
According to each of the second and fourth methods of the invention, it is essentially possible to complete the reaction in a single reaction vessel. Therefore, it becomes possible to remarkably simplify the reaction procedures. It is optional to the reaction, the reaction vessel may be cooled down, and then the contents of the reaction vessel are taken out. Then, an extraction solvent may be added to the contents, thereby separating solid matter. After that, volatile substances are distilled off from the filtrate, thereby obtaining the aimed product (e.g., the second palladium-complex compound in the case of the second method). If necessary, the aimed product can be purified through recrystallization, silica gel chromatography, or the like.
It should be noted that the second palladium complex compound Ar1xe2x80x94PdL2X used in the third method is not limited to the reaction product of the second method or the reaction step (a) of the first method and may be prepared by a conventional method, as disclosed in J. Organomet. Chem., 1971, 28, 287, Organometallics, 1996, 15(17), 3708, and J. Chem. Commun., 1994, 121.
The above-stated novel first and second palladium complex compounds according to the fifth and sixth aspects of the invention will be described in detail, as follows. The first palladium complex compound, which can be produced by the first, third or fourth method, is represented by the general formula (5): 
where Ar3 and Ar4 are respectively aryl groups represented by the above general formulas (6) and (7), and each L is independently a phosphine ligand. In the general formula (6) representing Ar3, R2 is trifluoromethyl group, trifluoromethyoxy group, a halogen that is fluorine, chlorine, bromine or iodine, nitro group, acetyl group, cyano group, an alkyl group having a carbon atom number of 1-4, an alkoxyl the reaction, the reaction vessel may be cooled down, and then the contents of the reaction vessel are taken out. Then, an extraction solvent may be added to the contents, thereby separating solid matter. After that, volatile substances are distilled off from the filtrate, thereby obtaining the aimed product (e.g., the second palladium-complex compound in the case of the second method). If necessary, the aimed product can be purified through recrystallization, silica gel chromatography, or the like.
It should be noted that the second palladium complex compound Ar1xe2x80x94PdL2X used in the third method is not limited to the reaction product of the second method or the reaction step (a) of the first method and may be prepared by a conventional method, as disclosed in J. Organomet. Chem., 1971, 28, 287, Organometallics, 1996, 15(17), 3708, and J. Chem. Commun., 1994, 121.
The above-stated novel first and second palladium complex compounds according to the fifth and sixth aspects of the invention will be described in detail, as follows. The first palladium complex compound, which can be produced by the first, third or fourth method, is represented by the general formula (5): 
where Ar3 and Ar4 are respectively aryl groups represented by the above general formulas (6) and (7), and each L is independently a phosphine ligand. In the general formula (6) representing Ar3, R2 is trifluoromethyl group, trifluoromethyloxy group, a halogen that is fluorine, chlorine, bromine or iodine, nitro group, acetyl group, cyano group, an alkyl group having a carbon atom number of 1-4, an alkoxyl group having a carbon atom number of 1-4, or an alkoxycarbonyl group having a carbon atom number of 2-5. Examples of these alkyl group, alkoxy group and alkoxycarbonyl groups of Ar3 are the same as the above-stated examples of those groups of Ar1. In the general formula (7) representing Ar4, R1 is trifluoromethyl group. Examples of the aryl group Ar4 are (1) aryl groups each having one trifluoromethyl, such as 2-trifluoromethylphenyl, 3-trifluoromethylphenyl, and 4-trifluoromethylphenyl, and (2) aryl groups each having two trifluoromethyl groups, such as 2,3-bis(trifluoromethyl)phenyl, 2,4-bis(trifluoromethyl)phenyl, 2,5-bis(trifluoromethyl)phenyl, 2,6-bis(trifluoromethyl)phenyl, 3,4-bis(trifluoromethyl)phenyl, and 3,5-bis(trifluoromethyl)phenyl. Of these, an aryl group having two trifluoromethyl groups is preferable, and 3,5-bis(trifluoromethyl)phenyl is more preferable. Thus, the palladium complex compound represented by the general formula (5) is preferably one represented by the following general formula: 
where R2, m and L are defined as above in accordance with the fifth aspect of the invention. Furthermore, it is more preferably one represented by the following general formula: 
where R2, m and L are defined as above in accordance with the fifth aspect of the invention. Similar to the aryl groups Ar1 and Ar2, the aryl group Ar3 is preferably one in which at least one of R2 is trifluoromethyl group. Examples of the aryl group Ar3 are the same as those of the aryl groups Ar1 and Ar2. The aryl group Ar3 may have at least two substituents. These at least two substituents may be any arbitrary combination of various substituents. One of the at least two substituents of the aryl group Ar3 is preferably trifluoromethyl group. Nonlimitative examples of such aryl group Ar3 are the same as those of the aryl groups Ar1 and Ar2. The aryl group Ar3 is preferably one having at least two trifluoromethyl groups. Examples of such aryl group are the same as those of the aryl group Ar1 or Ar2. Further nonlimitative examples of the aryl group Ar3 are the same as those of the aryl group Ar1 or Ar2.
As stated above, the second palladium complex compound according to the sixth aspect of the invention, which can be produced by the second method, is represented by the general formula Ar5xe2x80x94PdL2X where Ar5 is bis(trifluoromethyl)phenyl group, X is a halogen that is fluorine, chlorine, bromine or iodine, and each L is independently a phosphine ligand. Examples of the aryl group Ar5 are 2,3-bis(trifluoromethyl)phenyl, 2,4-bis(trifluoromethyl)phenyl, 2,5-bis(trifluoromethyl)phenyl, 2,6-bis(trifluoromethyl)phenyl,. 3,4-bis(trifluoromethyl)phenyl, and 3,5-bis(trifluoromethyl)phenyl. Of these, 3,5-bis(trifluoromethyl)phenyl is more preferable. The second palladium complex compound may be represented by the following general formula: 
where Ph is phenyl group, and X is a halogen that is fluorine, chlorine, bromine or iodine. Preferable examples of the second palladium complex compound are those represented by the following general formulas: 
where Ph is phenyl group, Tolyl is tolyl group, and n-Bu is n-butyl group. Of these, more preferable examples are those represented by the following formulas. 
The phosphine ligand of each of the novel first and second palladium complex compounds is not particularly limited, and may be the same as the phosphine used in the first to fourth methods. Therefore, all the above descriptions of the phosphine used in the first to fourth methods is applicable to that of the novel first and second palladium complex compounds.
Each of the novel first and second palladium complex compounds can be crystalline, can be dissolved in various organic solvents, thereby becoming stable. Furthermore, these compounds are each stable in the air at room temperature. Due to such physical and chemical properties of these compounds, it becomes easy to isolate these compounds, thereby making them high in purity. Furthermore, it is easy to store these compounds, thereby making them easy to be handled in an industrial scale use. Each of the novel first and second palladium complex compounds has catalytic activity in various reactions, such as (1) carbonylation of an aromatic compound through an insertion of monoxide or the like into a halogenated aryl and the subsequent reductive release, (2) vinylation through an insertion of olefin into a halogenated aryl and the subsequent reductive release, and (3) coupling of a halogenated aryl. For example, an example of the novel first palladium complex compound, [3,5-bis(trifluoromethyl)benzoato]3xe2x80x2,5xe2x80x2-bis(trifluoromethyl)-phenylbis(triphenylphosphine)palladium(II), represented by the following formula, has catalytic activity in vinylation through an insertion of olefin into a halogenated aryl and the subsequent reductive release. 
The novel second palladium complex compound may serve as an intermediate for producing a palladium complex compound having different ligands. An example of the novel second palladium complex compound, bromo[3,5-bis(trifluoromethyl) phenyl]bis(triphenylphosphine)palladium(II), represented by the following formula, has catalytic activity in the above-mentioned carbonylation, vinylation, coupling, and the like. 
The novel second palladium complex compound can be used as catalyst (Cat. Pd) in a reaction represented by the following reaction formula: 
wherein each of R6, R7 and R8 is independently an inert functional group. Examples of such inert functional group are alkyl groups of C1-C8, such as methyl, ethyl, isopropyl, n-butyl, t-butyl, and diisopropylmethyl. This reaction can be conducted by using a solvent, such as methanol, ethanol, isopropanol, benzene, toluene, ethyl acetate, THF, methylene chloride, 1,2-dichloroethane, or acetone. The amount of the novel second palladium compound is preferably of about 0.01-20 mol %, more preferably of about 0.05-10 mol %, based on the number of moles of the substrate. Furthermore, the reaction may be conducted for about 10-100 hr at a temperature of about 10-100xc2x0 C., preferably about 20-70xc2x0 C., to complete the reaction. These conditions of the reaction may be modified depending on the amount(s) of the reactant(s).